:# Start with the default settings. When you install Iptables in CentOS it already has some rules predefined. You will get the default rules if you restart the iptables service.:# Save your rule in a bash script (.sh file) so you don't lose it and can rerun it easily.

<ol><li value="3">If your command didn't work - the easiest thing to do is:<ul><li>Reload the default rules. You can do that by restarting the iptables service (you can also do that at the beginning of your shell script).</li><liThen li>Then run your script with all the working iptables commands that you already finished.</li><li>Go back to writing the rule that didn't work.</li></ul></li></ol>